package jdbc;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * 预编译SQL语句
 * 当SQL语句中需要含有用户提供的数据时，为了避免因为拼接SQL导致语义发生改变(SQL注入攻击)
 * 我们可以使用预编译SQL，先将数据部分用"?"占位，
 */
public class JDBCDemo7 {
    public static void main(String[] args) {
        UserInfo userInfo = InputUtil.getInputObject(new UserInfo(),"欢迎登录","登录");
        try(Connection connection = DBUtil.getConnection())
        {
            String sql = "SELECT id,username,password,nickname,age " +
                    "FROM userinfo " +
                    "WHERE username = ? AND password = ?";
            PreparedStatement ps = connection.prepareStatement(sql);
            ps.setString(1,userInfo.getUsername());
            ps.setString(2,userInfo.getPassword());
            ResultSet rs = ps.executeQuery();
            if (rs.next()){
                System.out.println("登录成功,欢迎你:"+rs.getString("nickname"));
            }else {
                System.out.println("登录失败");
            }
        }catch(SQLException e){
            throw new RuntimeException(e);
        }
    }
}
